Find and Read your Owner's Manual!

[OsoMoore]

I acquired (most of) the owner's manual for my 79 SC, and have been reading through it. There are a lot of things I didn't know, as well as some things that are generally awesome.

• Gas tank is 21.13 gallons. I thought it was ~16.
• Recommended gas is 87 Octane. I thought I needed 93.
• Apply Glycerin or Talcum to rubber seals to keep it soft and avoid cracking

Awesome charts of HP, gear ratios, etc.



Go get a copy and read it!

[S2GART]

When Porsche switched to the 3.2 engine, they added electronic fuel injection and required Premium gas. I too was surprised when I bought my SC that I could get away with 87. That can come in handy money wise when you are filling up 21 gallons. Here in CT 93 octane cost $4.30 a gallon......you do the math

I too was impressed with the owner's manual. In all the cars I have owned, I have never seen a power graph and shift point graph.

[kach22i]

I've read that Premium gas is cheap insurance against engine knocking on older less than perfect running engines.

Also read that you may not feel or hear it knocking, but damage can be done just the same. If you hear or feel some knocking it's too late, the damage is done.

The most curious thing I found out when reading my owners manual, was the location of the intermittent windshield wiper control. Somehow, it was alway behind a blind-spot, and located on the dash just behind the steering wheel. Not where I would have expected it at all.

[1982911SCTarga]

Best opening line in the history of owner's manuals:

Judging by the car you have chosen, you are a motorist of a special breed, and you are probably no novice when it comes to automobiles.

I always thought the sentence following that should have been:

Which is good, because our heating, ventilation and air conditioning systems are designed to confuse and befuddle the finest minds.

Brian

[OsoMoore]

Originally Posted by kach22i

I've read that Premium gas is cheap insurance against engine knocking on older less than perfect running engines.

Also read that you may not feel or hear it knocking, but damage can be done just the same. If you hear or feel some knocking it's too late, the damage is done.

That is disconcerting. Can anyone share some direct experience? I'm also going to hunt about with the search function.

[wgerow]

Originally Posted by OsoMoore

That is disconcerting. Can anyone share some direct experience? I'm also going to hunt about with the search function.

Look at it this way:
Assume you drive 5000 miles/yr
Assume you average 20 mpg
Assume 30 cent difference regular to premium
Therefore 250 gal/year.
Savings of using regular over premium: $75
Cost of a new engine overhaul: Thousands ($10K??)

I am really cheap. But we are talking about $75-$200 a year depending on how many miles you drive. You probably spend $75 just purchasing the oil every time you do an oil change. I don't risk it, I use Premium.

[prebordao]

I don't know if a modern 911 manual has the same detail. Can anyone chime in ?

Anyway, in the "old days" car manuals were a lot more technical. I remember seeing the manual for my father's early 60's Beetle and it had detailed cross drawings of the body, engine and gearbox ! How many would care about that now ?

[OsoMoore]

Originally Posted by wgerow

Look at it this way:
Assume you drive 5000 miles/yr
Assume you average 20 mpg
Assume 30 cent difference regular to premium
Therefore 250 gal/year.
Savings of using regular over premium: $75
Cost of a new engine overhaul: Thousands ($10K??)

I am really cheap. But we are talking about $75-$200 a year depending on how many miles you drive. You probably spend $75 just purchasing the oil every time you do an oil change. I don't risk it, I use Premium.

I just reached the same conclusion. And I only pay ~$0.20 more per gallon, so I'm closer to $50 a year. That pretty much settles it for me.

[Paulporsche]

When you look @ octane requirements, make sure you are quoting RON, MON or PON (RON+MON/2) figures. PON (US & Canada) figures are about 4 or 5 lower than RON (European) but are equivalent.

[SilberUrS6]

Originally Posted by 1982911sctarga

best opening line in the history of owner's manuals:

judging by the car you have chosen, you are a motorist of a special breed, and you are probably no novice when it comes to automobiles.

i always thought the sentence following that should have been:

which is good, because our heating, ventilation and air conditioning systems are designed to confuse and befuddle the finest minds.

brian

lol.

[lupin..the..3rd]

Originally Posted by wgerow

I am really cheap. But we are talking about $75-$200 a year depending on how many miles you drive. You probably spend $75 just purchasing the oil every time you do an oil change. I don't risk it, I use Premium.

$75 per year difference... that's $6.25 per month. You can't even buy one fast-food lunch for that.

"Saving money" by using 87 octane instead of 93 is fool's economy.

[Jerome74911S]

Well, there you go. I hadn't done the math, but now that I see it, the best premium gas, only.

[porwolf]

Originally Posted by OsoMoore

That is disconcerting. Can anyone share some direct experience? I'm also going to hunt about with the search function.

Since I got my 79SC in 1979 I have driven it for 50,000 miles with only regular gasoline. I was convinced that the low compression ratio of the 79 SC of only 8.5:1 does not require any higher octane rating. Also I never experienced knocking under any condition. Sure, higher octanes don't seem to hurt but I don't think they are necessary for a compression of 8.5:1. The reason for the low compression ratio, at the time, for the 79 SC was that it reduces dramatically the NO2 of the exhaust. Porsche at the time compensated the lower compression performance with the higher 3L displacement engine for the SC models.

[will hung]

Originally Posted by prebordao

I don't know if a modern 911 manual has the same detail. Can anyone chime in ?

Anyway, in the "old days" car manuals were a lot more technical. I remember seeing the manual for my father's early 60's Beetle and it had detailed cross drawings of the body, engine and gearbox ! How many would care about that now ?

I know the 993's have max speed in each gear published. My old neighbor had bought one and was shocked to see that in a manual.